Machine tool clamping mechanism



p 1949- I B. R. PURVIN 1 2,482,126

MACHINE TOOL CLAMPING MECHANISM Original Filed Sept. 3, 1958 2 Sheets-Sheet 1 INVENTOR. .Ben 'amin R. Pun in ATTORNEYS Sept. 20, 1949. B. R P RVIN. 2,482,126

MACHINE TOOL CLAMPING MECHANISM Original Filed Sept. 5, 1938 2 Sheets-Sheet 72 E'Lgfi. Z 55 3 INVENTOR. B am/n R. Parr/n ATTORNEYS Patented Sept. 20, 1949 MACH NE TQOI; CLAMBING- MEGHANISM;

Benjamin B. Purvin, Detroit, Mieln, assi nor to Barber-Colman Company; Rockford, Ill., a corporation of Illinois.

O inal application. September.- 3, 1338,, S r l No... 228,3 2, new a nt N 2,356d96l dated. August .9,, 1944, Divided; a d h s; appl ation August- 2.2., 1944., SerialNo. 550,559

The present invention relates generally to improvements in machinetools, and has particular reference toa machine tool having new and improved clamping means for securing a translatable. element in position of adjustment.

One of the objects of the invention is to pro vide a novel arrangement of hydraulic clamps operable siml-lltaneouslyto secure the translat able'element to a supporting column.

' Anotherobject is to provide a new and improved clampingmechanism which is simple in construction and which is powerful and efficient in operation.

Other objects and advantages will become apparent as the description proceeds.

In the accompanying drawings:

Figure 1 isa front elevational view of a ma chine tool having clamping means embodying the features of my invention.

Fig. 2 is a fragmentary diagrammatic representation of the hydraulic system.

Fig. 3 is a sectional View on an enlarged scale of the work slide clamping means.

Fig. 4 is a fragmentary vertical sectional view taken along line 4--4 of Fig 3.

Fig. 5 is a fragmentary sectional view taken along line 5-5 of Fig. 1, and illustrating means for adjusting and positioning the work slide.

Referring more particularly to the drawings, the present invention is embodied in a hobbing machine of the type disclosed my copending application, Serial No. 228,312; filed September 3, 1938, now Patent No. 23563796, issued August 29, 1944, of whichv the present application is a division.

The hobbing machine comprises a hollow base and upright columns 2 and 3 are rigidly mounted respectively on opposite ends. A work slide 4 is mounted for verticalpositioning on the front of the column 2, and has an integral over-arm 5 guided on the front of the column 3. Journaled inthe slide 4 is a hollow work spindle 5' adapted to be connected to one end of a work arbor 1 supporting a gear blank W. The other end of the arbor l is adapted to be supported by a tailstock 8 mounted for adjustment on the underside of theover-arm- 5. A hob slide 9 is mounted onthe top of the bed I' for travel axially of the spindle 6. A swivel plate I0 is mounted on the slide 9 for angular adjustment about a vertical axis, and adjustably supports a spindle slide H. J our-naled in the slide H is a spindlel2 adapted to support a cutting tool or hob T.

The work slide 4 is movable hydraulically eitherinto an elevated inoperative position or a lowered 6= Glaims. (CL camp 7 21 operative position, and is'adaptedto be'clampcd' hydraulically in the operative position. These positions are defined by a non-rotatable vertical screw l3 (see Fig. 5) threaded through a rotary nut. i4 journalcd in a lug ii on the rear of the slide 41.. lChe upper end of the screw l3 carries an abutment plate 96 adapted for engagement with he underside of a forwardly projecting lug H on the column 2 to define the inoperative position, and has an axial extension W of reduced diam-- eter extending slidably'through the lug. The lower end of the screw i3 is splined for axial movement through a mg I! on the rear and adjacent the bottom of the slide 4, and is adapted for engagement with a positive stop 20 on the bed i to define the operative position. The screw it is vertically adjustable relative to thework slide 4 to establish precisely'the desired depth of out. Thusa spiral gear 2I coaxial andrigid with the'l ow-erend or the nut M meshes with a spiral pinion 22 fixed on the inner end of a shaft journaled in the slide. 8 and extending theret-h'rough tothe front of the machine. A micrometer dial 24 is fixed on the front end ofthe shaft 23 to indicate the depth adjustmen-t. A locking screw 25 is threaded through the slide 4 for engagement-J with the periphery of the nut H! to, secure the stop screw it releasabl'y in position.

Vertical movement of the work slide l between; the limit positions is obtained by a hydraulic cylinder and piston motor 26 (see Fig. 2') rigidly mounted on the base and having a vertical piston rod 2? extending upwardly into operative engagement with the bottom of the slide body.

The work slide 6 is confined for vertical movement against the column 2 by suitable gib'plates 28%( see Figs; 3 and 4)' bolted in position. Adjustably' mounted in the plates- 28 are suitable tapered gibs 29- engaging rear clamping surfaces as on the column. A plurality of hydranl'ically operable clamps 3i, four in the: pres-' ent, instance and located ri-zspectively= adjacent. the ends-oi the gih plates 28, are arranged to' coact with the gibs 29- to secure the slide A? rigidly" in operative position. These clamps preferably are alike in 'constuction. and hence a description of one will sufilce for all.

Each of the clamps 3% comprises a cylindrical plunger 32 which is slidable in a tranverse bore 33 opening to the front of the work slide t, and which intermediate its ends is formed with a longitudinal diametrical slot 3%. The rear end of the plunger 32' has an axial stem 35. which extends slid'ably through a bore 36 to the rear of the work slide 4, and then ireelzy through a transverse notch 31 in the inner face of the gib plate 28 and a bore 38 opening from the notch to the rear of the gib plate. A clampingblock 39 is slidably disposed on the stem 35 within the notch 31, and is formed in one end with a notch 40 interfitting with and engaging the taper gib 3 29. A collar 4| is slidably disposed on the stem Extending transversely through the slot34 is a wedge member 43 in the form of a flat tapered bar adapted to impart a forward thrust to the plunger 3| to apply the clamp block v39. The wedge bar 43 is in antifriction bearing engagevalve being adapted to pass fluid when the pressure rises above a predetermined amount, as it will after the slide 4 has come to rest in operative position. The line 62 is adapted to be connected by a valve 63 to a line 64 connected in common to all of the clamp cylinders 52. A hand lever 65 on the front of the slide 4 is available for operating the valve 63 which in one position serves to connect the line 62 to the line 64 to applythe clamps, and in the other position to connect the line 64 to an exhaust line 66 to release the clamps. Hence, the valve 63 affords means forreleasing. and applying the clamps at will when the slide 4 is held in lowered position. The mechanism; for adjusting and clamping the work slide is disclosed and claimed in my ment at opposite sides with two rollers 44 dis-. posed within the slot 34. One of the rollers 44 bears against a hardened block 45 removably secured by a screw 46 against the forward end of the, slot; 34. The other roller 44 bears against the forward edge 41 of a hardened pin 48 extending transversely'through the bore 33 and the slot 34. The pin 48 is inserted in a transverse bore 48 in the s de of the'work slide 4, and is flattened to interfit slidably with the slot 34, thereby restraining the plunger 3| against rotation. a

The wedge bar 43 extends into the bore 33 from the interior of the work slide 4 through a transverse bore 49 closed at the outer end by a cap and is rigidly connected at the inner end to a piston 5| reciprocable in a hydraulic cylinder 52 ada ted to receive pres ure fluid. A coiled compression spring 53 en aging the piston 5| tends to retract the bar 43. It will be understood that when pressure fluid is sunnlied to the cylinder 52 the bar 43 will be forced outwardly, and through the rollers 44 rolling on the block 45 and the pin 48 will impart a powerful clamping thrust to the nlunger, 3|. 7 V v The p stons 5| for the two u per clam s, and also the pistons for the two lower clam s. in each instance are disposed in o posite ends. of one cylinder 52. In add tion to the four clamps for the work slide. a s milar hydraulicallv ooerable clam 54 is provided for securing the oyer-arm 5 to the face of the column 3. This clamp comprises a headed bolt (not shown) movable in a verticalT-slot 56 in the column 3 and connected to .a plunger 3| operable by a hydraulic motor including a cylinder 52. The cylinders 52 for the five clamps may be connected in parallel as more fully described in connection with the hydraulic circuits so that the clamping pressure atall points is equalized.

The hydraulic actuator 26 for elevating and lowering the work slide 4 has up er and lower fluid sunnly lines 51 and 58. The line 58 is connec ed through a resistance valve 59 to a line 60. the purpose of this resistance valve being to hold u the slide 4 when fluid pressure is not available. The lines 5'1 and 60 are adapted to be reversibly connected res ectively to 'a suitable source of pressure fluid (not shown) and exhaust. it' being understood that-when fluid is supplied to the line 6|! the slide will be elevated, and-when fluid is supplied to the line 51 the slide will be lowered. I

The various clamns 3! and 54 for the work slide 4 .are ada ted to be a lied simultaneously copending divisional application, Serial No. 98,929, filed June 14, 1949.

I claim as my invention:

1. In a machine tool,: in combination, a base having a column with verticalparallel spaced ways, a slide reciprocable on-the front of said Ways, gib plates on said slide and confining said slide on said Ways, taper gibs in said plates and engaging the rear of said ways, and a plurality of;

clamps for securing said slide in positionof adjustment, each clamp comprising a reciprocable plunger in said slide having a longitudinal dia-j metrical slot and having a clamping block adapted for coaction with the rear of the associated gib, a stop pin extendingthrough said slot, a

stop abutment in one end of said slot,,a wedge bar extending transversely through said slot betweensaid pin and abutment, antifriction rollers disposed against opposite sidesv of said barrand,

with, afixed abutment in said slide in opposed relationto said first ;mentioned abutment, a clamping blockon said plunger adapted for coaction with the rear of one of said Ways, a wedge bar extending transversely of said plunger for coaction with saidabutments, and hydraulic means for actuating said bar to apply and release,

said clamping block.

3. A clamping mechanism for an element reciprocable on a support comprising, in combina-,-

tion, a gib plate on said element and confining said element on said support, a'taper gib in said plate and engaging said support, a reciprocable plunger in said element having a-longitudinal diametrical slot and having a clamping block adapted for coaction with said gib, a stop pin supported in said element and extending through said slot, a stop abutment in oneend of said slot, a wedge bar extending transversely through said slot between said pin and abutment, antifriction rollers disposed against opposite sides of 1 said bar and coacting with said pin and said abut,

ment, spring means tending to retract said bar,

and means for actuating said bar against .the; action of said-springmeans to apply said block.

4. A clamping mechanism for an;element reciprocable on a support comprising, in combination, a gibplateon said element, and confining said element on said support, a reclprocable plunger in said element having a longitudinally facing abutment, an opposed abutment in said support, a clamping block on said plunger and adapted for coaction with said support to clamp said element in position, a wedge bar extending transversely of said plunger for coaction with said abutments to adjust said plunger longitudinally, and means for actuating said bar whereby to apply and release said block.

5. In a machine tool, in combination, a base, a machine element slidable on said base, and a clamping mechanism for securing said element in position of adjustment to said base, said clamping mechanism comprising a plunger reciprocably supported in said element and having a longitudinal slot opening transversely therethrough, a clamping block rigid with said plunger and movable therewith for coaction with said base to clamp said element to said base, a stop pin supported in said element and extending transversely through said slot, a stop abutment in said slot and disposed in opposed relation to said pin, a wedge bar extending transversely through said slot between said pin and abutment, antifriction rollers disposed against opposite sides of said bar and coacting with said pin and said abutment, and means for actuating said bar reversibly and including a hydraulic actuator for shifting said bar in a direction to apply a clamping pressure.

6. In a machine tool, in combination, a base, a. machine element slidabl on said a a d a clamping mechanism for securing said element in position of adjustment to said base, said clamping mechanism comprising a plunger reciprocably supported in said element and having a longitudinal slot opening transversely therethrough, a clamping block rigid with said plunger and movable therewith for coaction with said base to clamp said element to said base, a stop pin supported in said element and extending transversely through said slot, a stop abutment in said slot and disposed in opposed relation to said pin, a wedge bar extending transversely through said slot between said pin and abutment adapted upon movement in one direction to separate said pin and abutment so as to impart a clamping force to said block, and means for actuating said bar.

BENJAMIN R. PURVIN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,961,259 Trosch June 5, 1934 2,036,483 Lawrence Apr. '7, 1936 2,052,249 Roehm Aug. 25, 1936 2,123,825 DeVlieg July 12, 1938 2,146,446 Schmidt et al. Feb. 7, 1939 2,251,016 Gallimore July 29, 1941 2,355,677 Eansome Aug- 1 1 4 

